The invention relates to an arrangement for constant feeding of yarn to textile machines, particularly to knitting machines, where a continuously constant amount of yarn supplied to the operating system is required. The arrangement comprises a cage drum provided on its circumference with stable bolts, whereon a number of yarn windings are wound on, with a device for shifting these windings on the cage drum.
One of the known arrangements for the constant feeding of yarn comprises a system of rotatably arranged feeding rollers distributed along the circumference of a knitting machine and guiding an endless band driven by the drive of the machine. The proper feeding of yarn to the knitting system is accomplished by taking along the yarn between the endless band and a roller. As there is contact of the yarn with the feeding band on a small section only, the yarn slides, resulting in different speeds of the feeding band and thus also of the supplied yarn, so that the consumption of yarn is not uniform for all systems of the knitting machine. A consequence thereof is that the manufactured knitted goods are not uniform and their quality is lower.
A feeding arrangement is furthermore known wherein two endless feeding bands, one on the other, are guided by a system of rollers. The yarn is supplied between these feeding bands. A drawback of this solution is a considerable length of the internal feeding band, causing its delay and thus also non-uniform amounts of supplied yarn, particularly in the course of the starting and stopping of the machine.
Another known arrangement has for each feeding roller a coordinated auxiliary roller, whereby an individual feeding band encompasses both said rollers, the supplied yarn being taken along at given places between both bands. An advantage of this arrangement is a reduced possibility of the winding-on of a torn yarn on the feeding roller; otherwise this arrangement has the same drawbacks as the afore-mentioned arrangements.
Many of these mentioned drawbacks are eliminated in feeding arrangements where each feeding head is made so as to permit the winding of several windings of yarn on its drum, as is, for instance, described in the specification of an author's certificate of an invention of the USSR No. 519,513. In another similar solution, the deposition of these windings and their subsequent shifting is accomplished on a head with a cage drum, for instance by means of an inclined shifting sheet or by an indented wheel. There is, however, a rather high friction when shifting the yarn.
The same drawback is experienced when using two bolt cages, one stable, the other performing an axial and radial movement, as is, for instance, described in published German patent specification DAS No. 1,967,177.
Another known arrangement uses for the depositing and shifting of yarn windings an inclined arranged conical toothed wheel engaging with its teeth with bolts on the circumference of a feeding roller, on which yarn windings are deposited. The toothed wheel constantly shifts the yarn windings by the lateral face of its teeth. A drawback of this solution is that the movements of the toothed wheel and of the yarn from the axial and radial direction are added, causing a substantial abrasion of the yarn. The small diameter of the conical toothed wheel required by the construction causes a shifting of the yarn on a rather short, almost point section, causing a relatively high stress of the yarn on a small part of the circumference of the feeding roller.